Delactosed Whey Permeate as Substrate for Succinic Acid Fermentation by Actinobacillus succinogenes

Delactosed whey permeate (DLP) is the remnant after the concentration of deproteinized whey permeate and separation of the lactose. As the milk industry expands, the surplus of the waste product DLP increases. This work evaluates DLP for succinic acid production in batch cultures with mildly halotolerant Actinobacillus succinogenes 130Z. The elemental composition of delactosed whey permeate is analysed, adjusted by supplementing with peptone and NaHCO3, and used in submerged fermentations. The obtained succinic acid yield with DLP based media is ranged between 0.62 and 0.67 gSA/gLactose, with minimal by-products. Growth (K-x) and non-growth (m(ATP)) associated maintenance energies of A. succinogenes were estimated via ATP balance using batch fermentation data on both DLP media as well as conventional simulated media (TSB). For m(ATP), the estimated value is 7.4 mmol/gDCW/h for DLP media, which is compatible with commercial TSB media. Herein, we clearly demonstrate use of delactosed whey permeate as a promising substrate for succinic acid fermentation, despite high ionic strength and osmotic pressure potential.